2005 yukon xl thermostat question

Discussion in 'GM Powertrain' started by Pikey, Dec 31, 2013.

  1. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    Hi Guys and Girls,
    I have a 2005 yukon xl with a 5.3L. I replaced the thermostat last summer. Here is the issue that I am seeing now. (may not be an issue) I can start the truck and drive it, it warms up to operating temperature as it should. But, when just idling it does not get to the operating temp. I can drive it at operating temp and all is fine. When I idle for around 5 minutes the temp drops significantly. (it is 15 degrees here now) When I start driving the temp goes right back up to where it should be within a mile or so. So, my question is, should I put a new t-stat in it again? I have owned 3 5.3L and never noticed this before. @j cat , @RayVoy, @99'HEARTBEAT , opinions guys? everyone else feel free to chime in.
    here is a pic of just above where it drops to, it goes to the line just below the needle. it is the lower right gauge :

    View attachment 1231132101.jpg
     
    Last edited: Dec 31, 2013
  2. 99'HEARTBEAT

    99'HEARTBEAT Epic Member Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Mike....I also replaced the thermostat back in August of this year, and once my Engine a "5.3L" is up to Normal Operating Temps, Gauge reads around, 180/190 Degrees...and as far as I can tell, it doesn't drop like yours.

    By chance do you have anyway to check with a DTC Reader, with a Scanner, so you can see some Live Logging Data for the Gauge??
     
  3. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    I do have a Jet programmer with a monitor function. It reads a lower temp at idle. looks like I may replace the t stat later this morning. I need to see if one of the managers I know at the parts store is working so they can warranty it for me. Oddly, I can not find that receipt.
     
  4. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Mike, I think Mike (@99'HEARTBEAT) has the right suggestion (and he beat me, haha). It does sound like the t-stat is not closing to hold the heat in the engine.

    Did you guys have a good New Year's eve?
     
  5. 99'HEARTBEAT

    99'HEARTBEAT Epic Member Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor


    Morning Ray, and Happy New Year, it was a quiet one for me and my wife, and how was yours??

     
  6. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    We had planned to have a couple of couples over, but, as it turned out, it was the coldest night this winter and they decided to stay home. I don't blame them, they had a 10 mile drive and no one wanted to get into a cold car at 2am.

    So, I watched "the festivities on tv and was asleep by 1am (Margot didn't make 12am, haha).
     
  7. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    I changed out the t-stat this morning. After a quick test drive I let it idle in the garage for a few minutes and the temp dropped to 170.5. I topped off the coolant and drove it around for a while. I let it idle with the heaters (front and rear) on full blast for 20 minutes. The lowest it went on my monitor was 185.0 as soon as I touched the gas it dropped to 183.2. I drove around and while driving it is at 199.2 to 205.0 depending on how much I am on the gas. As of right now I am calling it fixed. I guess I will see over the next few days. Thanks for the help guys!
     
  8. 99'HEARTBEAT

    99'HEARTBEAT Epic Member Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor


    Ya Mike, It sounds like got this issue fixed........BTW Happy Year!!....:party:
     
  9. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Happy New Year [MENTION=51590]Pikey[/MENTION]
     
  10. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    Happy New Year Guys! :party:
     

Share This Page

Newest Gallery Photos